This transmission was precise with the tolerances for the bearing locations, the case halves and how they fit as well as the gear teeth on the mod 1 gears. Everything was a perfectly tight fit with extremely smooth operation once on my rig. I did a few test runs on 3, 4, and 6s with my Castle Creations Mamba X 1515 combo and I snapped an MIP axle and did so on the bone itself. I thought for sure the teeth would shear in my transmission being Aluminum and they were in perfectly intact when I stripped don my tranny. Don't think about it, buy it and never eat your transmission gears again!!!!! Super satisfied and FLM customer for life!!!